Why does nom expect a &str when I pass a CompleteStr?
The parser works as expected until I want to parse the h:
digit which is always the last digit in the string and the compiler gives me
^ expected &str, found struct `nom::types::CompleteStr`
I assume it's because the parser is looking ahead. How do I stop that, or how can I signify it's done?
#[macro_use]
extern crate nom;
use nom::digit;
use nom::types::CompleteStr;
use std::str::FromStr;
#[derive(Debug, PartialEq)]
pub struct Order {
pub l: u64,
pub w: u64,
pub h: u64,
}
named!(order_parser<CompleteStr, Order>,
do_parse!(
l: map_res!(digit, u64::from_str) >>
tag!("x") >>
w: map_res!(digit, u64::from_str) >>
tag!("x") >>
h: map_res!(digit, u64::from_str) >>
(Order {l: l, w: w, h: h })
)
);
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<&str>> {
order_parser(order)
}
#[test]
fn test_order_parser() {
assert_eq!(
wrap_order(CompleteStr("2x3x4")),
Ok((CompleteStr(""), Order { l: 2, w: 3, h: 4 }))
);
}
rust nom
add a comment |
The parser works as expected until I want to parse the h:
digit which is always the last digit in the string and the compiler gives me
^ expected &str, found struct `nom::types::CompleteStr`
I assume it's because the parser is looking ahead. How do I stop that, or how can I signify it's done?
#[macro_use]
extern crate nom;
use nom::digit;
use nom::types::CompleteStr;
use std::str::FromStr;
#[derive(Debug, PartialEq)]
pub struct Order {
pub l: u64,
pub w: u64,
pub h: u64,
}
named!(order_parser<CompleteStr, Order>,
do_parse!(
l: map_res!(digit, u64::from_str) >>
tag!("x") >>
w: map_res!(digit, u64::from_str) >>
tag!("x") >>
h: map_res!(digit, u64::from_str) >>
(Order {l: l, w: w, h: h })
)
);
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<&str>> {
order_parser(order)
}
#[test]
fn test_order_parser() {
assert_eq!(
wrap_order(CompleteStr("2x3x4")),
Ok((CompleteStr(""), Order { l: 2, w: 3, h: 4 }))
);
}
rust nom
1
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29
add a comment |
The parser works as expected until I want to parse the h:
digit which is always the last digit in the string and the compiler gives me
^ expected &str, found struct `nom::types::CompleteStr`
I assume it's because the parser is looking ahead. How do I stop that, or how can I signify it's done?
#[macro_use]
extern crate nom;
use nom::digit;
use nom::types::CompleteStr;
use std::str::FromStr;
#[derive(Debug, PartialEq)]
pub struct Order {
pub l: u64,
pub w: u64,
pub h: u64,
}
named!(order_parser<CompleteStr, Order>,
do_parse!(
l: map_res!(digit, u64::from_str) >>
tag!("x") >>
w: map_res!(digit, u64::from_str) >>
tag!("x") >>
h: map_res!(digit, u64::from_str) >>
(Order {l: l, w: w, h: h })
)
);
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<&str>> {
order_parser(order)
}
#[test]
fn test_order_parser() {
assert_eq!(
wrap_order(CompleteStr("2x3x4")),
Ok((CompleteStr(""), Order { l: 2, w: 3, h: 4 }))
);
}
rust nom
The parser works as expected until I want to parse the h:
digit which is always the last digit in the string and the compiler gives me
^ expected &str, found struct `nom::types::CompleteStr`
I assume it's because the parser is looking ahead. How do I stop that, or how can I signify it's done?
#[macro_use]
extern crate nom;
use nom::digit;
use nom::types::CompleteStr;
use std::str::FromStr;
#[derive(Debug, PartialEq)]
pub struct Order {
pub l: u64,
pub w: u64,
pub h: u64,
}
named!(order_parser<CompleteStr, Order>,
do_parse!(
l: map_res!(digit, u64::from_str) >>
tag!("x") >>
w: map_res!(digit, u64::from_str) >>
tag!("x") >>
h: map_res!(digit, u64::from_str) >>
(Order {l: l, w: w, h: h })
)
);
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<&str>> {
order_parser(order)
}
#[test]
fn test_order_parser() {
assert_eq!(
wrap_order(CompleteStr("2x3x4")),
Ok((CompleteStr(""), Order { l: 2, w: 3, h: 4 }))
);
}
rust nom
rust nom
edited Nov 20 '18 at 15:50
Shepmaster
155k14307452
155k14307452
asked Nov 20 '18 at 1:22
PumphousePumphouse
1,2261122
1,2261122
1
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29
add a comment |
1
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29
1
1
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29
add a comment |
1 Answer
1
active
oldest
votes
The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str
works on &str
, not CompleteStr
.
You can fix your parsers to use u64::from_str
correctly this way:
do_parse!(
l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
(Order { l: l, w: w, h: h })
)
There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {
order_parser(CompleteStr(order))
}
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str
works on &str
, not CompleteStr
.
You can fix your parsers to use u64::from_str
correctly this way:
do_parse!(
l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
(Order { l: l, w: w, h: h })
)
There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {
order_parser(CompleteStr(order))
}
add a comment |
The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str
works on &str
, not CompleteStr
.
You can fix your parsers to use u64::from_str
correctly this way:
do_parse!(
l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
(Order { l: l, w: w, h: h })
)
There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {
order_parser(CompleteStr(order))
}
add a comment |
The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str
works on &str
, not CompleteStr
.
You can fix your parsers to use u64::from_str
correctly this way:
do_parse!(
l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
(Order { l: l, w: w, h: h })
)
There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {
order_parser(CompleteStr(order))
}
The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str
works on &str
, not CompleteStr
.
You can fix your parsers to use u64::from_str
correctly this way:
do_parse!(
l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
tag!("x") >>
h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>
(Order { l: l, w: w, h: h })
)
There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:
pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {
order_parser(CompleteStr(order))
}
edited Nov 21 '18 at 18:52
answered Nov 20 '18 at 8:31
Valentin LorentzValentin Lorentz
6,77253555
6,77253555
add a comment |
add a comment |
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1
I believe your question is answered by the answers of Why does my nom parser not consume the entire input, leaving the last piece unparsed? / Parsing an integer with nom. If you disagree, please edit your question to explain the differences. Otherwise, we can mark this question as already answered.
– Shepmaster
Nov 20 '18 at 2:48
I changed it as I read up and still can't seem to get it to work
– Pumphouse
Nov 20 '18 at 4:29